arm64: dts: rockchip: rk3566: Add Radxa Compute Module 3

arm64: dts: rockchip: rk3566: Add Radxa Compute Module 3

Radxa Compute Module 3(CM3) is one of the modules from a series
System On Module based on the Radxa ROCK 3 series and is compatible
with Raspberry Pi CM4 pinout and form factor.

Specification:
- Rockchip RK3566
- up to 8GB LPDDR4
- up to 128GB high performance eMMC
- Optional wireless LAN, 2.4GHz and 5.0GHz IEEE 802.11b/g/n/ac wireless,
  BT 5.0, BLE with onboard and external antenna.
- Gigabit Ethernet PHY

Radxa CM3 needs to mount on top of this IO board in order to create
complete Radxa CM3 IO board platform.

Since Radxa CM3 is compatible with Raspberry Pi CM4 pinout so it is
possible to mount Radxa CM3 on top of the Rasberry Pi CM4 IO board.

linux-next commit for the same,

commit <8f19828844f2> ("arm64: dts: rockchip: Fix compatible for Radxa
CM3")

Add support for Radxa CM3.

Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Co-developed-by: FUKAUMI Naoki <naoki@radxa.com>
Signed-off-by: FUKAUMI Naoki <naoki@radxa.com>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>